<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
    </style>
</head>
<body>
    
</body>
<script>

    // 只要被引号包裹的数据，都是字符
    // console.log( "hello world" );
    // console.log( 'hello world' );
    // console.log( '345' );
    // console.log( 'true' );
    // console.log( '{}' );
    // console.log( '[]' );
    // console.log( 'function(){}' );
    // console.log( 'null' );
    // console.log( 'undefined' );


    console.log( typeof 'function(){}' );
    console.log( typeof 345 );
    console.log( typeof -345 );
    console.log( typeof -3.45 );
    console.log( typeof 3.45 );
    console.log( typeof NaN );
    console.log( typeof true );
    console.log( typeof {} );
    console.log( typeof [] );
    console.log( typeof function(){} );
    console.log( typeof undefined );

    console.log( typeof null );

    // 面试题：如何区分对象，数组，null
    // 第四周揭晓


    /*
    
    这
    是
    注
    释
    
    console.log( 12312323 )

    */

    console.log("hello world");
    
</script>
</html>